Wells are drilled into the earth's crust using a drilling rig. Tabular strings are lengthened by threadably coupling add-on tubular segments to the proximal end of the tubular string. The tabular string is generally suspended within the borehole using a rig floor-mounted spider as each new tubular segment or stand is coupled to the proximal end of the tubular string just above the spider. A single joint elevator is used to grip and secure the segment or stand to a hoist to lift the segment or stand into position for threadably coupling to the tubular string.
For installing a string of casing, existing single joint elevators generally comprise a pair of hinged body halves that open to receive a tubular segment and close to secure the tubular within the elevator. Elevators are specifically adapted for seeming and lifting tubular members having conventional connections. A conventional connection comprises an internally threaded sleeve that receives and secures an externally threaded end from each of two tubular segments to secure the segments in a generally abutting relationship. The internally threaded sleeve is first threaded onto the end of a first tubular segment to form a “box end.” The externally threaded “pin end” of the second tubular segment is threaded into the box end to complete the connection between the segments. Typical single joint elevators have a circumferential shoulder that forms a circle upon closure of the hinged body halves. The shoulder of the elevator engages the tubular segment under a shoulder formed by the end of the sleeve and the tubular segment. However, conventional single joint elevators cannot grip a tubular segment having integral connections, because there is no sleeve to form a circumferential shoulder.
Conventional elevators are also difficult to use on tabular segments that are not conveniently accessible. For example, casing segments are often moved to the rig floor from a horizontal pipe rack and presented to the rig floor at a “V”-door. A conventional single joint elevator requires enough clearance to close the hinged body halves around the tubular segment. Depending on the length of the tubular and the proximity of the floor or other rig structures, there may be insufficient clearance around the circumference of the tubular segment for gripping with a conventional single joint elevator, often requiring repositioning of the casing segment so that the single joint elevator can grip the tubular segment. Even if repositioning of each segment takes only a few seconds, delays for repeatedly repositioning tubular segments in the V-door consume a substantial amount of rig time.
What is needed is a single joint elevator that is securable to a tubular at any position along the length of the tubular segment, and not only at the sleeve. What is needed is a single joint elevator that is adapted for securing to the tubular segment notwithstanding close proximity of the rig floor or other rig structure. What is needed is a single joint elevator that can grip and lift single tubular segments without repositioning the tabular segment. What is needed is a versatile single joint elevator that facilitates lifting both a tubular segment having integral connections and a tubular segment having conventional connections with a threaded sleeve received onto the end of a threaded tubular segment.